Diagnostic Fine Needle Aspiration in a Case of Riedel’s Thyroiditis

In Riedel’s thyroiditis, a rare chronic inflammatory disease of thyroid gland, fine needle aspiration is usually non-diagnostic because most often only follicular cells are obtained and not the fibrous material characteristic of this type of thyroiditis. Therefore the diagnosis is often only established by histopathologic study of the surgically obtained biopsy. The illustrated case is a 46-year-old female who presented with a firm, non-mobile thyroid nodule of the left lobe. Fine needle aspiration was performed, demonstrating fragments of fibrous tissue and few inflammatory cells including neutrophils and lymphocytes, findings that could be representative of Riedel’s thyroiditis. Frozen section examination during subsequent surgery and later histopathologic study confirmed the diagnosis. Fine needle aspiration of the thyroid, if successfully done, could be highly suggestive for Riedel’s thyroiditis.